Mavic Air2s normal flight, on RTH, dropped into the sea.

[marcosvc]

On a normal flight, 6 min flight returning using RTH, the drone turned off and dropped into the sea.
Follow attached the flight log, and some prints from Airdata and Phanton Help.
Does anyone have a guess about what happened? My Guess is that the battery jumped off (I don't know why).
Any help are welcome.

 

[slup]

...My Guess is that the battery jumped off (I don't know why).

Certainly a possibility... but it's much better if you could share either the whole .TXT log or at least the link to the log at PhantomHelp/Airdata.

 

[StantonZ]

Is that a brand new battery (it says "times charged = 1")? Like you never flew it before "charging up" this first time?
Based on the fact that all the data shown looks "normal", I suppose it's possible the battery gave out. If you had flown it at least once (especially enough to require a second charge), it may have uncovered some defect.

 

[Yorkshire_Pud]

Is that a brand new battery (it says "times charged = 1")? Like you never flew it before "charging up" this first time?
Based on the fact that all the data shown looks "normal", I suppose it's possible the battery gave out. If you had flown it at least once (especially enough to require a second charge), it may have uncovered some defect.

Airdata's charge count thing counts the number of time that Airdata has noticed the charge level etc. increase.
Airdata's charge count is not accurate unless a flight log has been uploaded to Airdata after each charge of the battery.

 

[marcosvc]

DJI Flight Log Viewer - PhantomHelp.com

 

[Yorkshire_Pud]

Follow the log

I am not sure what you mean by that but if you want slup etc. to look at the log you would do best to post the URL of the Phantomhelp page that is shown in log9.png image of post #1 or the URL of the Airdata page shown in log1.png and make that page public.
The screen captures of post #1 are of very little use.

 

[marcosvc]

Not

I am not sure what you mean by that but if you want slup etc. to look at the log you would do best to post the URL of the Phantomhelp page that is shown in log9.png image of post #1 or the URL of the Airdata page shown in log1.png and make that page public.
The screen captures of post #1 are of very little use.

DJI Flight Log Viewer - PhantomHelp.com

 

[marcosvc]

does it shows now?

 

[Yorkshire_Pud]

does it shows now?

both the PH page and the .txt now show, thank you.

 

[Meta4]

DJI Flight Log Viewer - PhantomHelp.com

At the end of the flight the drone was in RTH, making a steady speed of 12 m/s.
There are no sudden changes in the pitch, roll or yaw data that would indicate a collision or show that the data continued after the fall started.

The data doesn't give any evidence of the cause of the fall, but helps eliminate most of the possible factors that might have happened.
That just leaves a sudden total loss of power as the most likely explanation for the incident.

 

[MavicAir2Marc]

I had the same thing happen on an Air 2S, very slight bulge in the battery, just enough to disconnect it but not enough to eject it. It fell right in front of me from about 20 feet in the air. When it hit the ground, the battery powered back up.

 

[slup]

The battery pops out airborne due to swelling... on a M2P.

 

[platty]

Wow .. that’s a worry. Must thoroughly check my batteries before each flight.I wonder if the swelling is very noticeable.

 

[slup]

Wow .. that’s a worry. Must thoroughly check my batteries before each flight.I wonder if the swelling is very noticeable.

You can't do much more than firstly mitigate the risk for gassing... meaning keeping the batteries above nominal voltage (storage voltage) as short time as possible (can mean that you don't wait for those 10 days it takes for the auto discharge function the batteries have). And never ever overheat the batteries (neither when they lay around or when flying).

Then secondly... regularly inspect them for swelling & if you notice even the slightest bulging you stop using them.

Also important to know that when a battery heats up a swelling can occur that then goes away when they cools down... so check for the swelling immediately when landed.

If you above all this, know that the battery attachment is sensitive + there is no available space between the drone & battery to take a small swelling during flight (like the Mavic 2 series) you can use something like below to strap the battery in so it doesn't gets dislodged.

 

[platty]

You can't do much more than firstly mitigate the risk for gassing... meaning keeping the batteries above nominal voltage (storage voltage) as short time as possible (can mean that you don't wait for those 10 days it takes for the auto discharge function the batteries have). And never ever overheat the batteries (neither when they lay around or when flying).

Then secondly... regularly inspect them for swelling & if you notice even the slightest bulging you stop using them.

Also important to know that when a battery heats up a swelling can occur that then goes away when they cools down... so check for the swelling immediately when landed.

If you above all this, know that the battery attachment is sensitive + there is no available space between the drone & battery to take a small swelling during flight (like the Mavic 2 series) you can use something like below to strap the battery in so it doesn't gets dislodged.

View attachment 173173

Thanks for your advice. Appreciate it

 

[platty]

The battery pops out airborne due to swelling... on a M2P.

 

[platty]

Wow, thanks for posting the video.Thats what I love about this forum. I have read posts of people saying how their drone just dropped out of the sky. The problem then highlited about the battery swelling. Advise from people on how to look after the batteries and after watching videos on it I am now following all instructions to the T. The thought of my expensive drone dropping into the water is scary. Living on a pension makes replacement extremely difficult indeed.

 

[platty]

Thanks for your advice. Appreciate it

Me again … a question about the Velcro strap to hold the battery in place as a precaution. Underneath my Air2s it looks like 2 sensors and inbetween the 2 sensors is a light. I am guessing it is only a light and therefore it would be ok if this was covered by the Velcro strap.would that be correct ?

 

[slup]

...Underneath my Air2s it looks like 2 sensors and inbetween the 2 sensors is a light. I am guessing it is only a light and therefore it would be ok if this was covered by the Velcro strap.would that be correct ?

Yes... most add on payload drop equipment cover it & are triggered by switching the light. Just make sure you don't strap in the battery release buttons & doesn't disturb any of the VPS sensors (#6 & 8).

 

[platty]

Yes... most add on payload drop equipment cover it & are triggered by switching the light. Just make sure you don't strap in the battery release buttons & doesn't disturb any of the VPS sensors (#6 & 8).

View attachment 173217

Thanks again